Engine Model: Redesigned SRM. Other Designations: Space Shuttle Solid Rocket Motor. Designer: Thiokol. Gross Mass: 569,893 kg (1,256,398 lb). Empty Mass: 66,406 kg (146,400 lb). Propellants: Solid. Thrust(vac): 11,520.000 kN (2,589,790 lbf). Isp: 269 sec. Burn time: 124 sec. Diameter: 3.85 m (12.62 ft). Length: 38.47 m (126.21 ft). Chambers: 1. Chamber Pressure: 46.00 bar. Area Ratio: 7.72. Country: USA. Status: In Production. Mass: 569,893 kg. Length: 38.47 m. Diameter: 3847 mm. Propellant Type: TP-H1148 HB Polymer, 16% Al, and 70% AP. Propellant Shape: 11-point star forward with a double taper cylinder . Propellant Mass Fraction: 0.883 (503,487 kg). Burn Time: 123.6 sec action, 111.7 sec web. Thrust: 11.52 MN average vacuum, and 14.77 MN maximum vacuum. Isp: 268.6 sec vacuum. Itotal: 296.3 MNs vacuum. Pressure: 62.4 atm maximum (MEOP 69.1) and 45 atm average. Nozzle Throat Diameter: 136.8 cm. Nozzle Length: 454 cm. Nozzle Exit Diameter: 380.1 cm (expansion ratio 7.72). Nozzle Materials: D6AC steel for fixed housing with throat and forward exit cone housings. aluminum for nose inlet and aft exit cone housing. Casing Materials: D6AC steel with 1.165 cm minimum thickness. Igniter: forward end internally mounted 62.1 kg of TP-H1178 case-bonded 40-point star.
Engine Model: SRB. Designer: Thiokol. Gross Mass: 589,670 kg (1,299,990 lb). Empty Mass: 86,183 kg (190,000 lb). Propellants: Solid. Thrust(vac): 11,519.800 kN (2,589,754 lbf). Thrust(sl): 10,149.400 kN (2,281,676 lbf). Isp: 269 sec. Isp (sea level): 237 sec. Burn time: 124 sec. Diameter: 3.71 m (12.17 ft). Length: 38.47 m (126.21 ft). Chambers: 1. Country: USA. Status: Study 1987. First Flight: 1981. Last Flight: 2003. Flown: 232. The decision to use segmented solid rocket boosters for the compromised space shuttle design, and the selection of Thiokol as the contractor, was fraught with political overtones. Aerojet in particular offered to build monolithic non-segmented SRB's from the Florida facility it had built in the 1960's for its 260 inch motors. The monolithic approach completely eliminated a number of potential failure modes, and should have resulted in considerably lower cost. One of these failure modes resulted in the Challenger disaster.
When the award to Thiokol was announced, Lockheed was so upset that they lodged a formal protest, but nothing ever came of it. Many years later, it was learned from a source close to the original source selection board that Thiokol was ranked fourth out of four by a wide margin. So, a new board had been convened, and strangely enough, Thiokol won. Many in the losing teams felt that this just may have been influenced by the fact that the Chairman of the Senate Space Committee was the senior senator from Utah. The selection of Thiokol was said to have been ordered directly from the Nixon White House. A similar situation occurred after the Shuttle disaster, with the decision, despite all that had happened, to continue with Thiokol's redesigned motors in lieu of solutions from other manufacturers (such as the cancelled ASRM).
SRB used on Rocket Stages
Bibliography:- Dorman, Bernie, et. al., Aerojet: The Creative Company, Stuart F Cooper Company, Los Angeles, 1995..